A polyimide resin excellent in heat resistance, mechanical characteristics and the like has been widely used for an interlayer insulation film, a surface-protecting film and the like for semiconductor elements in electronic instruments.
Additionally, a photosensitive polyimide resin to which photosensitivity is given for improvement of productivity, improvement of film forming accuracy and the like has been variously examined. For example, a negative type in which a photocrosslinking group is introduced into a polyimide precursor by ester bonding or ion bonding has been put into practice. Moreover, as a positive type, a composition of a polyimide precursor and an ortho-quinone diazide compound is described (See Patent Documents 1 and 2, and the like). However, the negative type has a problem in resolution and film formation, while the positive type has a problem in heat resistance, electrical insulation property, adhesion to a board and the like.
Other many patent documents have been filed, but characteristics required by higher integration, thinning and the like of the semiconductor element are not sufficiently satisfied. Further, there are problems of film thickness reduction (volume contraction rate) after hardening, requiring multistage baking for hardening, atmospheric control and the like so that the film can not be used easily in industrial applications is pointed out.
On the other hand, various photosensitive polyimide resins with photosensitivity imparted have been proposed in order to improve film forming accuracy according to higher integration of the semiconductor element. For example, Patent Documents 3 and 4 disclose a composition containing a photosensitive polyimide resin in which a photocrosslinking group is introduced into a polyimide precursor by ion bonding and a composition containing a photosensitive polyimide resin in which a photocrosslinking group is introduced into a polyimide precursor by ester bonding, respectively.
However, in these compositions, there is a defect that a closed loop process is required for imidization and since it is a solvent developing, resolution is not sufficient.
Patent Document 5 discloses a negative-type photosensitive composition in which a multi-functional acrylic compound is added to an aromatic polyimide precursor, but a problem similar to the above is pointed out.    [Patent Document 1]
Japanese Unexamined Patent Application Publication No. JP-A H05-5996    [Patent Document 2]
Japanese Unexamined Patent Application Publication No. JP-A 2000-98601    [Patent Document 3]
Japanese Unexamined Patent Application Publication No. JP-A S54-145794    [Patent Document 4]
Japanese Unexamined Patent Application Publication No. JP-A H03-186847    [Patent Document 5]
Japanese Unexamined Patent Application Publication No. JP-A H08-50354